Virginia, North Carolina, South Carolina and Georgia
VOC & Particulate Control
VOC & Particulate Control
VOC Control, Venturi & Cyclonic Scrubbers, Acid Gas Absorbers, and High Efficiency Cyclones.
NESTEC designs, furnishes, installs, and maintains oxidizers. They have been in business for more than 40 years and have a combined staff experience of over 300 years.
REGENERATIVE THERMAL OXIDIZERS
NESTEC regenerative thermal oxidizer’s (RTO) convert hazardous air pollutants (HAPs) and volatile organic compounds (VOCs) to carbon dioxide and water vapor through thermal oxidation.
The RTO technology is particularly economical for treating low-VOC-concentration process exhaust streams. They use regenerative heat transfer to achieve very high thermal efficiencies of 85 to 96 percent, which result in very low operating fuel costs — in some cases, zero.
Some of the industries RTO’s are successfully used in:
CATALYTIC THERMAL OXIDIZERS
NESTEC catalytic oxidizers use both precious and base metal catalysts, depending upon the application. The catalyst bed is designed into a recuperative oxidizer located between the inlet pass outlet of the heat exchanger and the combustion chamber. For systems that require a precious metal catalyst, NESTEC uses a coated ceramic monolith as provided by SŰD Chemie-Clariant.
The catalyst system can be cleaned periodically by removing the beads and tumble-cleaning them before returning them to the system. A small amount of make-up catalyst is typically required after cleaning
RECUPERATIVE THERMAL OXIDIZERS
The Recuperative Thermal Oxidizer converts VOCs and HAPs to carbon dioxide and water vapor through high-temperature oxidation. Operating temperatures are around 1,500°F. Thermal energy is recovered from the oxidation process by using a recuperative heat exchanger (either a plate type or shell-and-tube type) thereby lowering fuel costs.
Recuperative thermal oxidizers are less expensive than RTOs from a capital cost standpoint because they utilize lower-cost materials, and because they are smaller, using less material. Their design is simpler than an RTO, with fewer moving parts. However, fuel costs may be as high as six to seven times as much as an RTO because thermal efficiencies can only go as high as 65 percent. Despite these limitations, recuperative thermal oxidizers are a good fit for certain applications, and NESTEC has successful TOs operating throughout the USA.
DIRECT-FIRED THERMAL OXIDIZERS
The simplest technology of thermal oxidation is a direct-fired thermal oxidizer (sometimes called “afterburners”. The process exhaust stream of VOCs and HAPs is introduced into a firing chamber through/near a burner, and enough residence time is provided to achieve the desired destruction removal efficiency (DRE) of the VOCs. Most direct-fired thermal oxidizers operate at temperature levels between 1,800°F and 2,200°F, with air flow rates from 500 SCFM to 50,000 SCFM.
Direct-Fired Thermal Oxidizers are the least capital intensive — but when applied incorrectly, the operating costs can be substantial, because there is no form of heat recovery. These oxidizers are best used where there is a high concentration of VOCs to act as the fuel source for complete combustion at the targeted perating temperature.
Typical applications include treatment of airstreams having a BTU/SCF value of 500 or greater, such as landfill methane extraction off gas. Other applications include systems that require the mixing of upper flammability limit (UFL) gases with air.
Wet Scrubbers are devices that utilize some liquid (most often water) to remove contaminants from an exhaust gas stream. Wet scrubbers are named by the type of contaminant that they are designed to remove: particulate or gaseous.
Wet Scrubbers for Particulate Removal
Choosing a device to separate particulate from a gas stream is most often decided by looking at the lowest cost method of removing the particulate that also meets an allowable emission level. Many people assume that scrubbers are very expensive option. This assumption is often incorrect. Scrubbers themselves are very simple devices and are often the least expensive and most reliable device for removal of particulate from a gas stream. The long term capital and operating costs for any separation device is dependent on a number of variables. In the case of wet scrubbers, the cost analysis is often dependent upon the availability of water and the infrastructure for waste water treatment and/or disposal.
Some of the common process reasons for using scrubbers for particulate separation are;
Scrubbers are simple to build and operate. They can be engineered easily for very severe and/or variable operating conditions.
Wet scrubbers may be more compact than other dry devices.
Wet scrubbing may be the safest way of handling potentially explosive, pyrophoric, or combustible dusts.
Gaseous and particulate contaminants may be collected in the same device.
The most efficient way to cool high temperature process gases for treatment is by quenching with water. Once this is done, scrubbing with water for particulate removal is often the most economical and operable method for particulate separation.
Wet scrubbers can operate reliably on sticky and/or highly hygroscopic materials
HEC High-Efficiency Cyclones
High-Efficiency Cyclones are some of the simplest dust separation devices to build, however, it is very difficult to know what to build. Heumann’s experience and knowledge provides the foundation to engineer and build the high-efficiency cyclone that is right for your application.
Heumann applies the unparalleled ability to accurately predict the performance of every high-efficiency cyclone they manufacture. An empirically based model combines independent research and testing with over 80 years of published material using modern mathematical and statistical tools. This method provides the most accurate performance predictions over the broadest range of high-efficiency cyclone designs.
HEC High-Efficiency Cyclones
Regardless of the manufacturer, all high-efficiency cyclones are built one at a time. Why pay for custom “one off” manufacturing and not get the high-efficiency cyclone model and construction that is right for you? Heumann provides the knowledge and experience to ensure that the high-efficiency cyclone selected is the perfect fit for your process application.